Celestia Forums

Hello all,
I am new to this forum and was so excited to discover Celestia and this community. IRL few share such interests

I would like to ask a question that I cannot solve on my own please.

The light takes aproximately 8 mins to reach earth from the sun. However how much time does the light experience while making the trip? Meaning if someone traveled for 8 mins at the speed of light how much time would he count on his watch? The 8 mins are counted by someone outside the "vehicle".

The reason I am asking is because I was wondering if M31 is like 2.5 million light years away, how much time would we experience if we travelled there at the speed of light?

And if we travel faster than light what decides how long the trip should last? Like would it be instant or negative time and how much of it?

Thanks in advance

Travelling at the speed of light means time is standing still.

For the traveler looking out at the universe, they would see the universe aging, stars would be created and then die, galaxies would collided, and black holes burnout (theoretically they would see the end of the universe in an instant) because they would not age, but the universe world. From a person that is looking at the traveler, it would appear as if they were in stasis, and never aging.

Contrary to popular belief, going faster then light would not mean you would be able to travel backwards in time, or at least not in the conventional scene.

There are some interesting problems that arise if you were able to travel at the speed of light. The most paradoxical would be that of slowing down or stopping. Soon as you hit the speed of light, even if you slowed down in the next instant, the entire universe would have aged an eternity, so you would have just blown right by M31 before you knew it.

That being said, you don't need to go at the speed of light, just fast enough so you can get there during your lifetime.

MKruer wrote:For the traveler looking out at the universe, they would see the universe aging, stars would be created and then die, galaxies would collided, and black holes burnout (theoretically they would see the end of the universe in an instant) because they would not age, but the universe world. From a person that is looking at the traveler, it would appear as if they were in stasis, and never aging. ...

WOW!!! So each time you turn on the lights, the light created sees the end of time??

So is everything set in stone? Does the "predetermination paradox" apply for the future too?

Sorry, that's not the way it works.
Photons have no rest mass and do not experience that kind of slowdown.

For an accurate technical response to your question, I'd suggest you post it to the
BAUT forum at http://www.bautforum.com/questions-answers/
There are many competent physicists there who will be delighted to explain all aspects of the problem.

Thank you very much for the link Selden. And many thanks to MKruer and Andy74 as well

selden wrote:Sorry, that's not the way it works.
Photons have no rest mass and do not experience that kind of slowdown.

For an accurate technical response to your question, I'd suggest you post it to the
BAUT forum at http://www.bautforum.com/questions-answers/
There are many competent physicists there who will be delighted to explain all aspects of the problem.

Was that directed at me or Deimos2k? If me I like to know where my logic went wrong? I know that a photon doesn't behave as in the example, but the question was if the traveler could experience, what it would be like.

MKruer,

I was primarily distressed that Deimos2k was able to misunderstand what you wrote to take it to apply to the photons themselves. And, of course, the implication that a body with mass could actually travel that fast. It's the subtle distinctions that matter in such descriptions. I can't describe them well myself, but many people frequenting BAUT can and do. Grant Hutchison spends much of his time there, for example.

selden wrote:MKruer,

I was primarily distressed that Deimos2k was able to misunderstand what you wrote to take it to apply to the photons themselves. And, of course, the implication that a body with mass could actually travel that fast. It's the subtle distinctions that matter in such descriptions. I can't describe them well myself, but many people frequenting BAUT can and do. Grant Hutchison spends much of his time there, for example.

Never thought about the fact that I can do that much better than any of the mentioned people? .


Fridger

Fridger,

I'm sure you can describe it correctly and precisely.

However, too few people have been able to understand some of your explanations.
The people who frequent BAUT seem to have a lot of patience and experience in clarifying technical issues for those people who have no education in physics.

selden wrote:Fridger,

I'm sure you can describe it correctly and preciselly.

However, too few people have been able to understand some of your explanations.

How do you know? Did people complain to you? or are you inferring from yourself to others?

Fridger

If I may here Good Doctor?

Your explanations are very much accurate and unarguable.
However, as you know from dealing with me in the past, I often
have very much trouble understanding your explanations.

This is certainly not due to the effort expended by yourself, but, rather, it
is the plain and simple fact that not everyone has the same amount
of brain cells that you do...

At any rate, I do very much appreciate your efforts in this regard.
Please don't stop trying to explain to us Brain-Dead types.

I actually do understand some of what you explain to us. And the more I
understand, the better prepared I am for your next explanation.

Thank you Sir..
Brain-Dead Bob

In any case it saves time NOT to explain anything.

Fridger

Fridger, I don't think anyone is trying to detract from you posting your explanations, however you should keep in mind that most people have a 2d view of the universe, and are not capable of understanding three dimensions yet. This is why when I post I try to give a simple analogy. Sure its not wholly correct, but its good enough to enlighten most people, or get them interested to know more. In fact I think i prefer the analogy to the tetchy details because its more of a challenge to find an analogy then just post a bunch of technobabble